Late in the afternoon of 4 June 2012 PDT (early on June 5 UTC), VENUS lost contact with the Delta Dynamics Laboratory (DDL) platform, an NRCan lead research initiative studying delta slope stability. The image shows the last minutes of data from the platform. 2 Nortek Vector ADVs connected to the DDL (one on the VIP frame and a second remotely deployed on its own tripod) were sampling at 16 and 8 Hz respectively. Shown here are the high-sample rate (16Hz) pressure readings from the downward facing Nortek Vector on the VIP and the 1 Hz internal compass headings (which may be suspect as the instrument becomes inverted). The data suggest the entire platform was tumbled several times westward into deeper water, until the data streams end at 00:04:03 [UTC].
Over the last two weeks VENUS and NRCan have been assessing the event through replaying the marine traffic scenarios, taking sediment cores, conducting multibeam surveys, assessing private vessel provided sonar data and most recently side-scan surveys of the area. On June 28, Adrian Round, working with Terra Remote, conducted 500kHz side-scan surveys that located the platform about 60m from its original location.
Although further diagnoses will continue, we plan to recover and assess the condition of the entire package during our August maintenance cruise. Dr. Gwyn Lintern at NRCan is investigating the cause of the event and we anticipate some interesting research results. For our initial investigations we are thankful to Department of Fisheries and Oceans scientists and crew on board the CCGS John P. Tully for collecting sediment cores, the crew of the University of New Brunswick survey vessel Heron for multibeam survey, the core analysis facility at Geological Survey of Canada Pacific for a quick response, a captain of a local Seaspan commercial vessel who sent in his observations, and the Marine Communications and Traffic Services, Canadian Coastguard.